Ah, yes.... the beloved packmule. As Chris Taylor so aptly put it... "Let's face it. The packmule rocks!" A fellow DS fan site is named Packmule.org and the web admin, Ahnteis Corazon, refers to himself as the Packmule King :) So what's so special about this furry four legged fella?

Simply, the packmule allows you to carry extra goods when you run out of space in your inventory, up to three times as much as you can carry as a matter of fact. You can hire a packmule in town and he becomes a full fledged member of the party, counting as one of the eight party members. And there's more :)
According to a GameSpot article:

These ill-tempered party members can even put the boot to enemies foolish enough to wander within range of their hooves.

And if the packmule happens to kick the wrong bad guy and he ends up getting killed off then you even have the option to resurrect your packmule! All of his inventory can then be picked up and placed back on one very grateful packmule.

Joe Kresoja, GPG artist, tells us a little bit more about the way the packmule will appear and how they learned how to animate a mule:

The pack mule is going to have different load states. When you buy him he'll come bare or he'll come out with basic carrying sacks. As you get more equipment he'll draw a different load state.

Lee Phemister is the pack Mule's father so to speak, he's the man who created and put the motion in the mule, among other things. We have tons of reference material on animals and skeletons and stuff like that. Lee rented some videos on horses and studied them a lot and there were some books that had good horse walk loops. One person has a great book on animals in motion with lots of good still frames.